The second year of the above stated project will consist of analysis of the following data (collected in the first year): 7-day urine collections, blood pressure, height, weight age, sex, race triceps skinfold and 3-day food records for 173 school children ages 11-14. Initial results clearly demonstrate the feasibility of using a 7-day collection of urine to characterize the individual. In addition, an unanticipated result - in view of the modest sample size - has been the finding of a positive association between sodium excretion and blood pressure. The measurement error arising from the large day-to-day variation in salt excretion can now be estimated and minimized.